1. Field of the Invention
The present invention relates to a wireless system and, more particularly, to an apparatus and method for improving a reception rate of a receiver comprising an automatic gain control and an I and Q offset correction function for compensating signal degradation characteristics is disclosed.
2. Description of the Related Art
Radio frequency bands are closely spaced between mobile communication providers. The close spacing near a base station causes degradation in a reception rate between mobile communication providers resulting in a coverage hole in mobile communication service. To improve the reception rate in a coverage hole, automatic gain control (AGC) circuitry is utilized to remove entirely or reduce at least partially modulation or saturation phenomenon generated within the mobile terminal. The automatic gain control circuitry measures the received electric field strength. A low noise amplifier adjusts a signal gain of a mobile terminal.
Referring to FIG. 1, a conventional receiver block comprises an RF unit 10 and a demodulator unit 20. The demodulator unit 20 detects a level of signal power in a power detector 40. The signal power is feedback to control a level for an automatic gain control amplifier.
Referring to FIG. 2, the process is illustrated for amplitude adjusting two channels of a receiver. An RF signal is demodulated into an I and Q channel signal. An offset power level is introduced while creating an I and Q channel signal. The I and Q channel signals are amplitude adjusted using baseband information from an a table 51. An AGC amplifier is controlled using baseband signal information located in the table 51 for amplitude adjusting the I and Q channel signals. An offset adjustment unit 50 comprising a level detector 52, the table 51, and a feedback network is required to correct for amplitude differences between the I and the Q channels. This offset adjustment unit is a complex circuit which introduces processing time delay.
Therefore, there is a need for a system that overcomes the above problems and provides advantages over other signal amplitude adjustment processing systems.